{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=High+Dose+Quadrivalent+Influenza+Vaccine&page=2",
    "query": {
      "intervention": "High Dose Quadrivalent Influenza Vaccine",
      "page": 2
    },
    "page_size": 10
  },
  "pagination": {
    "page": 2,
    "page_size": 10,
    "total_count": 56,
    "total_pages": 6,
    "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=High+Dose+Quadrivalent+Influenza+Vaccine&page=3&page_size=10",
    "previous_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=High+Dose+Quadrivalent+Influenza+Vaccine&page=1&page_size=10"
  },
  "source": "remote",
  "last_synced_at": "2026-10-07T11:29:23.891Z",
  "attribution": "Data derived from public ClinicalTrials.gov records. The official record at https://clinicaltrials.gov/ remains the source of truth for current availability, contacts, and full study details.",
  "notes": [
    "This endpoint exposes only public summary fields — no participant contact emails, phone numbers, or scraped investigator contact details.",
    "For contact information and full protocol detail, follow each trial's `official_url` to the ClinicalTrials.gov record.",
    "This API is a navigational aid. It does not provide medical advice, eligibility determinations, or compensation guarantees."
  ],
  "trials": [
    {
      "nct_id": "NCT03617523",
      "title": "Safety and Immunogenicity of Fluzone® Quadrivalent, Flublok® Quadrivalent, and Fluzone® High-Dose, Influenza Vaccines, 2018-2019 Formulations",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Fluzone Quadrivalent vaccine, 2018-2019 formulation",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Flublok Quadrivalent vaccine, 2018-2019 formulation",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluzone High-Dose vaccine, 2018-2019 formulation",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "6 Months",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "6 Months and older"
      },
      "enrollment_count": 240,
      "start_date": "2018-09-10",
      "completion_date": "2018-11-12",
      "has_results": true,
      "last_update_posted_date": "2022-03-29",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 3,
      "location_summary": "Bardstown, Kentucky • Metairie, Louisiana • Salt Lake City, Utah",
      "locations": [
        {
          "city": "Bardstown",
          "state": "Kentucky"
        },
        {
          "city": "Metairie",
          "state": "Louisiana"
        },
        {
          "city": "Salt Lake City",
          "state": "Utah"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03617523"
    },
    {
      "nct_id": "NCT04439695",
      "title": "Study to Evaluate the Safety and Immunogenicity of KBP-V001 Quadrivalent Influenza Vaccine in Healthy Adults",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "Low dose",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Intermediate dose",
          "type": "BIOLOGICAL"
        },
        {
          "name": "High dose",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Placebo",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "KBio Inc",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "49 Years",
        "sex": "ALL",
        "summary": "18 Years to 49 Years"
      },
      "enrollment_count": 120,
      "start_date": "2020-06-25",
      "completion_date": "2021-07-28",
      "has_results": false,
      "last_update_posted_date": "2021-09-16",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 1,
      "location_summary": "Omaha, Nebraska",
      "locations": [
        {
          "city": "Omaha",
          "state": "Nebraska"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04439695"
    },
    {
      "nct_id": "NCT03282240",
      "title": "Safety and Immunogenicity of High-Dose Quadrivalent Influenza Vaccine in Participants ≥65 Years in the US",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Influenza"
      ],
      "interventions": [
        {
          "name": "QIV-HD",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Licensed TIV-HD1",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Investigational TIV-HD2",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 2670,
      "start_date": "2017-09-08",
      "completion_date": "2018-04-19",
      "has_results": true,
      "last_update_posted_date": "2022-04-07",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 36,
      "location_summary": "Anaheim, California • Redding, California • San Diego, California + 29 more",
      "locations": [
        {
          "city": "Anaheim",
          "state": "California"
        },
        {
          "city": "Redding",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Colorado Springs",
          "state": "Colorado"
        },
        {
          "city": "Milford",
          "state": "Connecticut"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03282240"
    },
    {
      "nct_id": "NCT06361875",
      "title": "A Study to Investigate the Safety and Immunogenicity of the Quadrivalent Influenza mRNA Vaccines in Adults Aged 18 Years and Above",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Influenza Immunization",
        "Healthy Volunteers"
      ],
      "interventions": [
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5421",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5424",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5429",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza Standard Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Influenza High-Dose Vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Recombinant Influenza Vaccine",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 908,
      "start_date": "2024-04-01",
      "completion_date": "2025-06-09",
      "has_results": true,
      "last_update_posted_date": "2026-08-04",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 11,
      "location_summary": "San Diego, California • Hialeah, Florida • Hollywood, Florida + 8 more",
      "locations": [
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Hialeah",
          "state": "Florida"
        },
        {
          "city": "Hollywood",
          "state": "Florida"
        },
        {
          "city": "Indianapolis",
          "state": "Indiana"
        },
        {
          "city": "Lexington",
          "state": "Kentucky"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06361875"
    },
    {
      "nct_id": "NCT05426174",
      "title": "Study to Assess the Safety and Immunogenicity of Monovalent mRNA NA Vaccine in Adult Participants 18 Years of Age and Older",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Influenza Immunization",
        "Healthy Volunteers"
      ],
      "interventions": [
        {
          "name": "mRNA NA vaccine",
          "type": "BIOLOGICAL"
        },
        {
          "name": "High Dose Quadrivalent Influenza Vaccine",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 233,
      "start_date": "2022-06-09",
      "completion_date": "2024-01-03",
      "has_results": false,
      "last_update_posted_date": "2025-09-15",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 6,
      "location_summary": "Huntsville, Alabama • Phoenix, Arizona • San Diego, California + 3 more",
      "locations": [
        {
          "city": "Huntsville",
          "state": "Alabama"
        },
        {
          "city": "Phoenix",
          "state": "Arizona"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Melbourne",
          "state": "Florida"
        },
        {
          "city": "Peoria",
          "state": "Illinois"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05426174"
    },
    {
      "nct_id": "NCT05227001",
      "title": "A Study To Learn About The Study Vaccine (Called Self-Amplifying Ribonucleic Acid (RNA)) For The Prevention of Influenza",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Influenza, Human"
      ],
      "interventions": [
        {
          "name": "PF-07852352 Influenza saRNA 1",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07836391 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07836394 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07836395 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07836396 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07867246 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Placebo",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent influenza vaccine (QIV)",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07871987 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07914705 Influenza saRNA",
          "type": "BIOLOGICAL"
        },
        {
          "name": "PF-07915048 Influenza saRNA",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Pfizer",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "49 Years",
        "sex": "ALL",
        "summary": "18 Years to 49 Years"
      },
      "enrollment_count": 440,
      "start_date": "2022-04-28",
      "completion_date": "2023-08-04",
      "has_results": false,
      "last_update_posted_date": "2026-03-20",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 24,
      "location_summary": "Phoenix, Arizona • Walnut Creek, California • Greenacres City, Florida + 13 more",
      "locations": [
        {
          "city": "Phoenix",
          "state": "Arizona"
        },
        {
          "city": "Phoenix",
          "state": "Arizona"
        },
        {
          "city": "Phoenix",
          "state": "Arizona"
        },
        {
          "city": "Walnut Creek",
          "state": "California"
        },
        {
          "city": "Greenacres City",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05227001"
    },
    {
      "nct_id": "NCT04077424",
      "title": "Senescent Immunity in Elders and Vaccine Responses (SILVER)",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Flu Vaccine"
      ],
      "interventions": [
        {
          "name": "Fluzone-High Dose Quadrivalent",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Fluad",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Flublock",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Vanderbilt University Medical Center",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": "125 Years",
        "sex": "ALL",
        "summary": "65 Years to 125 Years"
      },
      "enrollment_count": 10,
      "start_date": "2019-10-21",
      "completion_date": "2020-02-01",
      "has_results": true,
      "last_update_posted_date": "2022-07-12",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 1,
      "location_summary": "Nashville, Tennessee",
      "locations": [
        {
          "city": "Nashville",
          "state": "Tennessee"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04077424"
    },
    {
      "nct_id": "NCT05663463",
      "title": "Seasonal Influenza Vaccine High Dose Boosting in Solid Organ Transplant Recipients",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "NA"
      ],
      "conditions": [
        "Solid Organ Transplant"
      ],
      "interventions": [
        {
          "name": "Fluzone High-Dose - 2 doses",
          "type": "DRUG"
        },
        {
          "name": "Fluzone High-Dose - 1 dose of HD",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "University of Minnesota",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 74,
      "start_date": "2023-09-11",
      "completion_date": "2025-06-16",
      "has_results": false,
      "last_update_posted_date": "2025-07-15",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 1,
      "location_summary": "Minneapolis, Minnesota",
      "locations": [
        {
          "city": "Minneapolis",
          "state": "Minnesota"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05663463"
    },
    {
      "nct_id": "NCT06029933",
      "title": "Fluad vs. Fluzone High-Dose Vaccine Effectiveness Among Adults ≥65 Years",
      "overall_status": "RECRUITING",
      "study_type": "OBSERVATIONAL",
      "phases": [],
      "conditions": [
        "Influenza",
        "Community-acquired Pneumonia",
        "Cardiovascular Events"
      ],
      "interventions": [
        {
          "name": "Adjuvanted Quadrivalent Inactivated Influenza Vaccine (aIIV4)",
          "type": "BIOLOGICAL"
        },
        {
          "name": "High-Dose Quadrivalent Inactivated Influenza Vaccine (HD-IIV4)",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Kaiser Permanente",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "65 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "65 Years and older"
      },
      "enrollment_count": 1500000,
      "start_date": "2023-08-17",
      "completion_date": "2028-05",
      "has_results": false,
      "last_update_posted_date": "2026-08-05",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 1,
      "location_summary": "Oakland, California",
      "locations": [
        {
          "city": "Oakland",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06029933"
    },
    {
      "nct_id": "NCT05624606",
      "title": "Safety and Immunogenicity of Quadrivalent Influenza mRNA Vaccine MRT5410 in Adult Participants 18 Years of Age and Older",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Influenza Immunization"
      ],
      "interventions": [
        {
          "name": "Quadrivalent Influenza mRNA Vaccine MRT5410",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Recombinant Influenza vaccine RIV4",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Inactivated Influenza Standard Dose QIV-SD",
          "type": "BIOLOGICAL"
        },
        {
          "name": "Quadrivalent Inactivated Influenza High Dose QIV-HD",
          "type": "BIOLOGICAL"
        }
      ],
      "intervention_types": [
        "BIOLOGICAL"
      ],
      "sponsor": "Sanofi Pasteur, a Sanofi Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 682,
      "start_date": "2022-11-28",
      "completion_date": "2024-03-28",
      "has_results": false,
      "last_update_posted_date": "2025-03-18",
      "last_synced_at": "2026-10-07T11:29:23.891Z",
      "location_count": 23,
      "location_summary": "Huntington Park, California • Long Beach, California • North Hollywood, California + 19 more",
      "locations": [
        {
          "city": "Huntington Park",
          "state": "California"
        },
        {
          "city": "Long Beach",
          "state": "California"
        },
        {
          "city": "North Hollywood",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Gainesville",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05624606"
    }
  ]
}